Include fcntl.h in s_audio_pa.c
This fixes the issue #850 by simply including fcntl.h
in the s_audio_pa.c
file.
I believe this is a safe/correct fix because the Pure Data vanilla also includes fcntl.h
in the s_audio_pa.c
file: https://github.com/pure-data/pure-data/blob/master/src/s_audio_pa.c#L29
After including fcntl.h
, I could compile Purr Data for the Desktop app using make light
without errors.